Cement-polyurethane composite grouting material suitable for reinforcing dense soft rock and preparation method thereof

Abstract

The application belongs to the technical field of tunnel and underground engineering disaster prevention and control, and particularly relates to a cement-polyurethane composite grouting material suitable for dense soft rock reinforcement and a preparation method thereof. The composite grouting material is mainly formed by mixing a penetration cross-linking liquid and a grout vein skeleton liquid. The penetration cross-linking liquid is formed by mixing a grouting material A component and a grouting material B component. A semi-prepolymer is obtained by pre-polymerization reaction of a polyisocyanate and a polyether polyol, and then a diluent and a catalyst are added to the semi-prepolymer to obtain the grouting material A component; a surfactant, a retarder and water are mixed to obtain the grouting material B component; and cement and water are uniformly mixed in a certain proportion to obtain the grout vein skeleton liquid. The cement-polyurethane composite grouting material and the preparation method thereof can achieve penetration-splitting composite reinforcement effect when grouting in a dense soft rock poor geological section with strong density and poor permeability, and the grout preparation process and grouting operation steps are more simple and efficient.

Description

Technical Field

[0001] This invention belongs to the field of disaster prevention and control technology for tunnels and underground engineering, specifically relating to a cement-polyurethane composite grouting material suitable for the reinforcement of dense soft rock and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] With the rapid development of infrastructure construction such as transportation, water conservancy and hydropower, a number of tunnels and underground projects of world-class scale and difficulty are under construction or about to commence. Due to complex geological conditions, the construction of many tunnels and underground projects will encounter adverse geological conditions such as weak surrounding rock and fault zones, which are prone to major geological disasters such as large deformation of soft rock, collapse of surrounding rock, mudslides and water inrushes, posing a great threat to the safety of the projects.

[0004] Soft surrounding rock, represented by water-rich sandstone and siltstone, is a common adverse geological type encountered in tunnels and underground engineering projects, and a significant source of risk leading to various disasters. These soft media typically have a loose structure, poor cementation, and low bearing capacity, but exhibit strong compactness under deep burial and high ground stress conditions. When a tunnel passes through dense, soft strata, the structure of the soft media loosens under the unloading action of excavation, easily leading to rock instability, collapse, and seepage damage. Grouting pre-reinforcement of dense soft rock is an important measure to ensure the safety of tunnel and underground engineering excavation. However, past engineering practices have shown that the surrounding rock in unexcavated tunnel sections maintains strong compactness (dense particles in weak media) due to minimal construction disturbance. When cement or clay-based grouts are used for pre-grouting, the grout has poor permeability and a small diffusion range, only forming a certain number of split grout veins. This makes it difficult to effectively reinforce and impermeable the strata outside the grout veins, often resulting in weak reinforcement zones between the grout veins. When organic materials such as acrylamide and urea-formaldehyde resin are used for grouting, the strength of the reinforced body is usually low, leading to poor reinforcement effects and varying degrees of environmental problems. To address the technical challenges of grouting reinforcement in dense soft rock, there is an urgent need to develop new grouting materials to provide material and technical support for disaster management in tunnels and underground engineering.

[0005] In recent years, various novel polyurethane-based grouting materials have been developed both domestically and internationally, demonstrating strong applicability in grouting reinforcement of weak surrounding rock. For example, patent CN114409367A provides a polymer composite grouting material based on a cement-water glass dual-slurry and high-molecular-weight polyurethane, which can be used for the rapid treatment of tunnel water and mud inrush disasters; patent CN113683369B develops a highly permeable dual-liquid grouting material based on the gelling properties of water-based polyurethane; and patent CN115140982A discloses a polyurethane-modified grouting material, which, after grouting modification, gives mudstone superhydrophobic properties while also being able to withstand the impact of circulating water. These grouting materials fully utilize the high permeability of water-soluble polyurethane, effectively increasing the diffusion range of the grout in dense, weak strata and reducing the permeability coefficient of the injected medium. However, they still suffer from low gelling strength and poor overall reinforcement effect, making it difficult to significantly improve the bearing capacity and self-stability of weak surrounding rock. Furthermore, the published patent CN115322301A proposes a composite two-component grouting material that is both permeable and splittable. Its principle involves using cement grout to form split grout veins, while simultaneously utilizing a low-viscosity permeable crosslinking liquid composed of polyurethane and acrylate to achieve effective permeation and diffusion in the area outside the grout veins. This grouting material has good effects on the reinforcement and anti-seepage treatment of dense and weak surrounding rock. However, its preparation process requires first preparing a grout vein skeleton liquid, mixing it with the permeable crosslinking liquid component A, and then adding the permeable crosslinking liquid component B to the mixture. This process is cumbersome and inefficient. Moreover, because it uses two organic raw materials, polyurethane and acrylate, the preparation process requires high precision. Summary of the Invention

[0006] To address the aforementioned issues, this invention proposes a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock and its preparation method, which can effectively reinforce and impermeable the dense and weak surrounding rock of tunnels and underground engineering projects.

[0007] This invention proposes a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock. The development concept is as follows: a high-viscosity, high-strength cement slurry is used as the grout vein skeleton fluid; a low-viscosity, highly permeable polyurethane solution generated through chemical reaction, along with various additives, is used as the permeation and crosslinking fluid. The two are mixed evenly to form the final cement-polyurethane composite grouting material. The addition of the aqueous polyurethane solution improves the uniformity of cement particle distribution in the slurry, while simultaneously delaying the cement hydration process, inhibiting the formation of ettringite in the hydration reaction, and promoting the formation of CSH gel and calcium hydroxide. This results in a more uniform arrangement of hydration product crystals, thereby improving the pore structure and effectively enhancing the strength and impermeability of the reinforced body. During grouting, the grout vein skeleton fluid, due to its high viscosity and high cement particle content, can form fracturing channels under high grouting pressure, driving the slurry to diffuse deep into the surrounding rock and form the grout vein skeleton. While the skeleton fluid splits dense soft rock, the permeating cross-linked fluid diffuses into the surrounding strata of the splitting channel, forming a larger grouting range and improving the pore structure and physical and mechanical properties of the weak medium. The aforementioned cement-polyurethane composite grouting material effectively solves the problem that solution-based materials only penetrate but do not split, making it difficult to meet reinforcement strength requirements. It also addresses the issue of poor permeability in dense soft strata, where conventional grouting materials struggle to penetrate and diffuse.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock, mainly composed of a penetrating crosslinking liquid and a grout vein skeleton liquid. The penetrating crosslinking liquid is formed by mixing grouting material component A and grouting material component B.

[0010] The grouting material A component is composed of a semi-prepolymer, a diluent, and a catalyst, with a mass ratio of 1:0.15-0.25:0.005-0.01. In addition, a small amount of additives may be added to the grouting material A component as needed to improve the stability of subsequent chemical reactions.

[0011] The grouting material B component is composed of water, surfactant and retarder, and the mass ratio of water, surfactant and retarder is 90-95:1-5:1-5.

[0012] The slurry skeleton fluid is made by uniformly mixing cement and water, with a cement-to-water mass ratio of 1:0.7 to 1.

[0013] Addressing the urgent need for reinforcement of dense soft rock in tunnels and underground engineering projects, and recognizing the shortcomings of existing technologies, this invention proposes a novel cement-polyurethane composite grouting material and its preparation method. When grouting in dense soft rock sections with high density and poor permeability, it achieves a combined permeability-fracture reinforcement effect. Furthermore, it boasts advantages such as simple grout preparation and convenient and efficient grouting operation, thus providing a new solution for grouting reinforcement and anti-seepage treatment of dense and weak surrounding rock.

[0014] A second aspect of the present invention provides a method for preparing a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock, comprising:

[0015] Step 1: Mix cement and water evenly in a certain proportion to obtain the grout vein skeleton liquid;

[0016] Step 2: The polyisocyanate and polyether polyol are subjected to a prepolymerization reaction to obtain a semi-prepolymer, which is composed of waterborne polyurethane. A certain proportion of diluent and catalyst are then added to the semi-prepolymer and mixed evenly to obtain grouting material component A.

[0017] Step 3: Mix the surfactant, retarder and water in a certain proportion to obtain component B of the grouting material;

[0018] Step 4: Mix component A of the grouting material with component B in a certain proportion to obtain a penetrating crosslinking liquid;

[0019] Step 5: Mix the permeation crosslinking liquid and the grout vein skeleton liquid in a certain proportion to obtain the cement-polyurethane composite grouting material.

[0020] The mixing mass ratio of grouting material component A to grouting material component B is 1:0.8 to 1; the mixing mass ratio of grout vein skeleton liquid to permeation crosslinking liquid is 1:0.8 to 1.2.

[0021] This invention provides a cement-polyurethane composite grouting material suitable for the reinforcement of dense soft rock and its preparation method, which can effectively solve the problems of grouting reinforcement and anti-seepage treatment of dense soft rock. It has great application value for ensuring the grouting reinforcement effect of dense soft rock tunnels and the safety of construction and operation.

[0022] Beneficial effects of the present invention

[0023] (1) The cement-polyurethane composite grouting material provided by this invention is composed of a grout vein skeleton liquid and a permeation crosslinking liquid. The cement grout, acting as the grout vein skeleton liquid, enables fracturing grouting, effectively solving the problem of low reinforcement strength and difficulty in meeting the stability requirements of surrounding rock for solution-based grouting materials. The water-based polyurethane solution generated through chemical reaction, along with various additives, acts as a permeation crosslinking liquid, capable of penetrating and diffusing a considerable distance along the fracturing channels, effectively addressing the problem of poor permeability in dense and weak strata and the difficulty of penetration and diffusion of conventional grouting materials. The cement-polyurethane grouting material exhibits a permeation-fracturing composite action mode in dense and weak strata, significantly improving the grouting diffusion range and grouting effect, and effectively solving the challenges of reinforcement and anti-seepage treatment in dense and weak strata.

[0024] (2) The cement-polyurethane composite grouting material provided by the present invention is a two-component grouting material with stable material properties. The gelation time can be optimized and adjusted according to the engineering needs, and it has good engineering applicability.

[0025] (3) The method for preparing cement-polyurethane composite grouting material provided by the present invention is simple and convenient to operate on site. A small amount of conventional equipment can complete the on-site preparation and grouting construction. Under the premise of ensuring the grouting effect, the grouting efficiency can be significantly improved. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is a physical effect diagram of the plasma vein skeleton fluid prepared in Example 1 of the present invention.

[0028] Figure 2 The images show the actual effects of grouting material component A and grouting material component B prepared in Example 1 of this invention.

[0029] Figure 3 This is a physical effect diagram of the permeation crosslinking liquid prepared in Example 1 of the present invention.

[0030] Figure 4 This is a physical effect diagram of the cement-polyurethane composite grouting material mixture prepared in Example 1 of the present invention.

[0031] Figure 5 This is a physical effect diagram of the cement-polyurethane composite grouting material prepared in Example 1 of the present invention for consolidating crushed rock.

[0032] Figure 6 This is a composition diagram of the cement-polyurethane composite grouting material prepared in Example 1 of the present invention.

[0033] Figure 7This is a schematic diagram comparing the working modes of the cement-polyurethane composite grouting material proposed in this invention with those of traditional grouting materials. Detailed Implementation

[0034] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] This invention provides a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock, which is composed of a grout vein skeleton liquid and a permeating crosslinking liquid mixed in a certain proportion, wherein the permeating crosslinking liquid is composed of grouting material component A and grouting material component B.

[0037] Another embodiment of the present invention provides a method for preparing a cement-polyurethane composite grouting material, comprising the following steps:

[0038] Step 1: Mix cement and water evenly in a certain proportion to obtain the grout vein skeleton liquid;

[0039] Step 2: The polyisocyanate and polyether polyol are subjected to a prepolymerization reaction to obtain a semi-prepolymer, which is composed of waterborne polyurethane. A certain proportion of diluent and catalyst are then added to the semi-prepolymer and mixed evenly to obtain grouting material component A. If necessary, a small amount of additives can be added to grouting material component A to improve the stability of subsequent chemical reactions.

[0040] Step 3: Mix the surfactant, retarder and water in a certain proportion to obtain component B of the grouting material;

[0041] Step 4: Mix component A of the grouting material with component B in a certain proportion to obtain a penetrating crosslinking liquid;

[0042] Step 5: Mix the permeation crosslinking liquid and the grout vein skeleton liquid in a certain proportion to obtain the cement-polyurethane composite grouting material.

[0043] The mass ratio of cement to water in the slurry skeleton fluid is 1:0.7 to 1, and the cement used is ordinary Portland cement.

[0044] The specific process for preparing the polyurethane semi-prepolymer in step two above is as follows: a certain proportion of polyether polyol is added to polyisocyanate at a temperature of 50°C, and after rapid stirring to make the two evenly mixed, the temperature is raised to about 85°C to carry out a prepolymerization reaction, thereby obtaining component A of the grouting material.

[0045] The polyether polyol is polyether 220, the polyisocyanate is polyphenyl polymethylene polyisocyanate (PAPI), and the concentration of isocyanate groups (-NCO) in the polyurethane semi-prepolymer generated by the prepolymerization reaction is 18-25%.

[0046] The diluent is one or more of dimethyl methylphosphonate, trichloroethyl phosphate, and divalent ester (DBE), and its content is 15-25% of the semi-prepolymer mass.

[0047] The catalyst is one or both of dibutyltin dilaurate and m-phenylenediamine, and its content is 0.5-1% of the mass of the semi-prepolymer.

[0048] The additives include fillers and stabilizers. The fillers are one or more of calcium carbonate, bentonite, and diatomaceous earth, and their content is 0-3% of the semi-prepolymer mass. The stabilizers are silicone oil, and their content is 0-3% of the semi-prepolymer mass.

[0049] Step two above involves mixing a surfactant, a retarder, and water in a specific ratio to obtain grouting material component B. The surfactant is one or both of lauryl alcohol and sodium dodecylbenzene sulfonate; the retarder is acetic acid. In grouting material component B, the mass ratio of surfactant, retarder, and water is 1–5:1–5:90–95.

[0050] The grouting material A component and grouting material B component are mixed to obtain a penetrating crosslinking liquid, and the mass ratio of the two components is 1:0.8 to 1.

[0051] The cement-polyurethane composite grouting material is obtained by mixing the permeation crosslinking liquid with the grout vein skeleton liquid, and the mass ratio of the two is 1:0.8 to 1.2.

[0052] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0053] In the following examples, the polyether polyol is polyether 220, the polyisocyanate is polyphenyl polymethylene polyisocyanate (PAPI), and the cement is ordinary silicate cement.

[0054] Example 1

[0055] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0056] 1. Preparation of plasma matrix fluid

[0057] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0058] 2. Preparation of the permeation crosslinking solution

[0059] (1) Preparation of Component A of Grouting Material

[0060] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was quickly stirred until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 25%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0061] Subsequently, 25 parts by mass of diluent (trichloroethyl phosphate), 1 part by mass of catalyst (dibutyltin dilaurate), 3 parts by mass of silicone oil, and 3 parts by mass of calcium carbonate were added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material was obtained.

[0062] (2) Preparation of component B of grouting material

[0063] Component B of the grouting material is obtained by mixing 5 parts by mass of surfactant (lauryl alcohol), 5 parts by mass of retarder (acetic acid), and 90 parts by mass of water and stirring thoroughly.

[0064] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0065] 3. Preparation of cement-polyurethane composite grouting materials

[0066] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0067] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 650 mPa·s. The gelation and curing time of the obtained composite grouting material is 35 min. The 7-day compressive strength of the solidified body obtained by grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 14.6 MPa.

[0068] Example 2

[0069] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0070] 1. Preparation of plasma matrix fluid

[0071] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0072] 2. Preparation of the permeation crosslinking solution

[0073] (1) Preparation of Component A of Grouting Material

[0074] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was quickly stirred until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 25%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0075] Subsequently, 25 parts by mass of diluent (which is a mixture of trichloroethyl phosphate and dimethyl methylphosphonate in a mass ratio of 1:1), 1 part by mass of catalyst (m-phenylenediamine), 3 parts by mass of silicone oil, and 3 parts by mass of bentonite are added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material is obtained.

[0076] (2) Preparation of component B of grouting material

[0077] Component B of the grouting material is obtained by mixing 5 parts by mass of surfactant (in which the mass ratio of lauryl alcohol to sodium dodecylbenzenesulfonate is 1:1), 5 parts by mass of retarder (acetic acid), and 90 parts by mass of water and stirring thoroughly.

[0078] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0079] 3. Preparation of cement-polyurethane composite grouting materials

[0080] After the grout vein skeleton liquid and the penetrating crosslinking liquid are mixed evenly at a mass ratio of 1:0.8, the cement-polyurethane composite grouting material is obtained.

[0081] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 650 mPa·s. The gelation and curing time of the obtained composite grouting material is 25 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 12.8 MPa.

[0082] Example 3

[0083] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0084] 1. Preparation of plasma matrix fluid

[0085] Add 500 parts by weight of cement to 500 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0086] 2. Preparation of the permeation crosslinking solution

[0087] (1) Preparation of Component A of Grouting Material

[0088] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was quickly stirred until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 25%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0089] Subsequently, 25 parts by mass of diluent (in which the mass ratio of dibutyltin dilaurate (DBE) to dibutyltin dilaurate is 1:1), 1 part by mass of catalyst (in which the mass ratio of m-phenylenediamine to dimethyl methylphosphonate is 1:1), 2 parts by mass of silicone oil, and 3 parts by mass of diatomaceous earth are added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material is obtained.

[0090] (2) Preparation of component B of grouting material

[0091] Component B of the grouting material is obtained by mixing 5 parts by mass of surfactant (sodium dodecylbenzenesulfonate), 5 parts by mass of retarder (acetic acid), and 90 parts by mass of water and stirring thoroughly.

[0092] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:0.8 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0093] 3. Preparation of cement-polyurethane composite grouting materials

[0094] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1.2, the cement-polyurethane composite grouting material is obtained.

[0095] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 650 mPa·s. The gelation and curing time of the obtained composite grouting material is 23 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 10.8 MPa.

[0096] Example 4

[0097] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0098] 1. Preparation of plasma matrix fluid

[0099] Add 500 parts by weight of cement to 425 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0100] 2. Preparation of the permeation crosslinking solution

[0101] (1) Preparation of Component A of Grouting Material

[0102] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was quickly stirred until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 25%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0103] Subsequently, 25 parts by mass of diluent (divalent ester (DBE)), 0.8 parts by mass of catalyst (dibutyltin dilaurate), 1 part by mass of silicone oil, and 3 parts by mass of bentonite were added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material was obtained.

[0104] (2) Preparation of component B of grouting material

[0105] The grouting material component B is obtained by mixing 5 parts by mass of surfactant (lauryl alcohol), 3 parts by mass of retarder (acetic acid), and 92 parts by mass of water and stirring thoroughly.

[0106] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0107] 3. Preparation of cement-polyurethane composite grouting materials

[0108] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0109] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 630 mPa·s. The gelation and curing time of the obtained composite grouting material is 37 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 16 MPa.

[0110] Example 5

[0111] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0112] 1. Preparation of plasma matrix fluid

[0113] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0114] 2. Preparation of the permeation crosslinking solution

[0115] (1) Preparation of Component A of Grouting Material

[0116] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was quickly stirred until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 25%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0117] Subsequently, 25 parts by mass of diluent (dimethyl methylphosphonate), 0.5 parts by mass of catalyst (dibutyltin dilaurate), and 3 parts by mass of silicone oil were added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material was obtained.

[0118] (2) Preparation of component B of grouting material

[0119] Component B of the grouting material is obtained by mixing 5 parts by mass of surfactant (lauryl alcohol), 1 part by mass of retarder (acetic acid), and 94 parts by mass of water and stirring thoroughly.

[0120] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0121] 3. Preparation of cement-polyurethane composite grouting materials

[0122] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0123] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 640 mPa·s. The gelation and curing time of the obtained composite grouting material is 28 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 13.3 MPa.

[0124] Example 6

[0125] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0126] 1. Preparation of plasma matrix fluid

[0127] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0128] 2. Preparation of the permeation crosslinking solution

[0129] (1) Preparation of Component A of Grouting Material

[0130] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was stirred rapidly until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was measured to be 22%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0131] Subsequently, 25 parts by mass of diluent (trichloroethyl phosphate), 1 part by mass of catalyst (dibutyltin dilaurate), and 3 parts by mass of silicone oil were added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material was obtained.

[0132] (2) Preparation of component B of grouting material

[0133] The grouting material component B is obtained by mixing 1 part by mass of surfactant (lauryl alcohol), 5 parts by mass of retarder (acetic acid), and 94 parts by mass of water and stirring thoroughly.

[0134] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0135] 3. Preparation of cement-polyurethane composite grouting materials

[0136] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0137] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is light yellow in appearance and has a viscosity of 660 mPa·s. The gelation and curing time of the obtained composite grouting material is 28 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 13.8 MPa.

[0138] Example 7

[0139] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0140] 1. Preparation of plasma matrix fluid

[0141] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0142] 2. Preparation of the permeation crosslinking solution

[0143] (1) Preparation of Component A of Grouting Material

[0144] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was stirred rapidly until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 20%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0145] Then, 20 parts by mass of diluent (trichloroethyl phosphate), 1 part by mass of catalyst (dibutyltin dilaurate), and 3 parts by mass of silicone oil are added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material is obtained.

[0146] (2) Preparation of component B of grouting material

[0147] The grouting material component B is obtained by mixing 1 part by mass of surfactant (lauryl alcohol), 5 parts by mass of retarder (acetic acid), and 94 parts by mass of water and stirring thoroughly.

[0148] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0149] 3. Preparation of cement-polyurethane composite grouting materials

[0150] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0151] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is dark yellow in appearance and has a viscosity of 680 mPa·s. The gelation and curing time of the obtained composite grouting material is 27 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 13.6 MPa.

[0152] Example 8

[0153] A cement-polyurethane composite grouting material and its preparation method, comprising the following steps:

[0154] 1. Preparation of plasma matrix fluid

[0155] Add 500 parts by weight of cement to 350 parts by weight of water and stir evenly for at least 3 minutes to obtain the grout vein skeleton liquid.

[0156] 2. Preparation of the permeation crosslinking solution

[0157] (1) Preparation of Component A of Grouting Material

[0158] 350 parts by mass of polyisocyanate were added to a suitable container and preheated to 50°C. Then, 80 parts by mass of polyether polyol were added to the polyisocyanate in two portions, and the mixture was stirred rapidly until homogeneous. The temperature of the mixture was then raised to approximately 85°C for a prepolymerization reaction. After the prepolymerization reaction had proceeded for a certain period, the mixture was sampled and tested. When the isocyanate group concentration was found to be 18%, a suitable polyurethane semi-prepolymer was obtained. The mixture was then cooled for later use.

[0159] Then, 15 parts by mass of diluent (trichloroethyl phosphate) and 1 part by mass of catalyst (dibutyltin dilaurate) are added to 100 parts by mass of polyurethane semi-prepolymer. After thorough mixing, component A of the grouting material is obtained.

[0160] (2) Preparation of component B of grouting material

[0161] The grouting material component B is obtained by mixing 1 part by mass of surfactant (lauryl alcohol), 5 parts by mass of retarder (acetic acid), and 94 parts by mass of water and stirring thoroughly.

[0162] The grouting material component A prepared in this embodiment is added to the grouting material component B at a mass ratio of 1:1 and mixed thoroughly to obtain the permeation crosslinking liquid.

[0163] 3. Preparation of cement-polyurethane composite grouting materials

[0164] After mixing the grout vein skeleton liquid and the permeation crosslinking liquid at a mass ratio of 1:1, the cement-polyurethane composite grouting material is obtained.

[0165] The viscosity of the permeation crosslinking liquid, the gelation and curing time of the cement-polyurethane composite grouting material, and the strength index of the pulverized rock solidified body were tested, and the results are as follows: The permeation crosslinking liquid obtained in this example is dark yellow in appearance and has a viscosity of 680 mPa·s. The gelation and curing time of the obtained composite grouting material is 27 min. The 7-day compressive strength of the solidified body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province is 13.5 MPa.

[0166] Comparative Example 1

[0167] The difference from Example 1 is that no surfactant was added. The results are as follows: the permeation crosslinking liquid obtained in this example was light yellow in appearance, with a viscosity of 600 mPa·s. The gelation and curing time of the resulting composite grouting material was 74 min. The 7-day compressive strength of the consolidated body obtained after grouting simulation of the pulverized rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province was 6.6 MPa. Therefore, the addition of surfactant improved the 7-day compressive strength of the cement-polyurethane composite grouting material.

[0168] Comparative Example 2

[0169] The difference from Example 1 is that no retarder was added. The results are as follows: The permeating crosslinking liquid obtained in this example was a milky white suspension with a viscosity of 930 mPa·s. The gelation and curing time of the resulting composite grouting material was 9 minutes. The 7-day compressive strength of the solidified body obtained after grouting simulation of the silty rock exposed during the construction of the Xianglushan Tunnel of the Dianzhong Water Diversion Project in Yunnan Province was 2.7 MPa. Therefore, the addition of the retarder prolonged the curing time of the cement-polyurethane composite grouting material and improved its 7-day compressive strength.

[0170] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cement-polyurethane composite grouting material suitable for reinforcing dense soft rock, characterized in that, The composite grouting material is mainly composed of a permeation crosslinking liquid and a grout vein skeleton liquid; the mass ratio of the permeation crosslinking liquid to the grout vein skeleton liquid is 1:1; wherein, the permeation crosslinking liquid is formed by mixing grouting material component A and grouting material component B; the mass ratio of grouting material component A to grouting material component B is 1:

1. The grouting material A component is composed of a semi-prepolymer, a diluent, and a catalyst, with a mass ratio of 1:0.25:0.008; the grouting material B component is composed of water, a surfactant, and a retarder, with a mass ratio of 92:5:

3. The surfactant is lauryl alcohol; the retarder is acetic acid; The slurry skeleton fluid is made by uniformly mixing cement and water; the mass ratio of cement to water is 1:0.

85. The semi-prepolymer is obtained by prepolymerization reaction of polyisocyanate and polyether polyol; the polyether polyol is polyether 220, and the polyisocyanate is polyphenyl polymethylene polyisocyanate. The permeation crosslinking liquid is light yellow in appearance and has a viscosity of 630 mPa·s; the 7-day compressive strength of the solidified body obtained after grouting simulation of the cement-polyurethane composite grouting material is 16 MPa.

2. A method for preparing a cement-polyurethane composite grouting material suitable for reinforcing dense soft rock, characterized in that, include: Step 1: Mix cement and water evenly in a certain proportion to obtain the grout vein skeleton liquid; The mass ratio of cement to water in the slurry skeleton fluid is 1:0.85; Step 2: A semi-prepolymer is obtained by prepolymerizing polyisocyanate and polyether polyol. The semi-prepolymer is composed of waterborne polyurethane. A certain proportion of diluent and catalyst are then added to the semi-prepolymer and mixed evenly to obtain grouting material component A. The content of the diluent is 25% of the mass of the semi-prepolymer; the content of the catalyst is 0.8% of the mass of the semi-prepolymer; the polyether polyol is polyether 220, and the polyisocyanate is polyphenyl polymethylene polyisocyanate. Step 3: Mix the surfactant, retarder, and water in a certain proportion to obtain Component B of the grouting material; the mass ratio of water, surfactant, and retarder is 92:5:3; the surfactant is lauryl alcohol; the retarder is acetic acid. Step 4: Mix component A of the grouting material with component B in a certain proportion to obtain a penetrating crosslinking liquid; The mass ratio of grouting material component A to grouting material component B is 1:

1. Step 5: Mix the permeation crosslinking liquid and the grout vein skeleton liquid in a certain proportion to obtain the cement-polyurethane composite grouting material; the mass ratio of the permeation crosslinking liquid to the grout vein skeleton liquid is 1:

1.

3. The preparation method of the cement-polyurethane composite grouting material suitable for reinforcement of dense soft rock as described in claim 2, characterized in that, The cement used is ordinary Portland cement.

4. The preparation method of the cement-polyurethane composite grouting material suitable for reinforcement of dense soft rock as described in claim 2, characterized in that, The preparation process of the semi-prepolymer is as follows: a certain proportion of polyether polyol is added to polyisocyanate at a temperature of 50~55℃, and after rapid stirring to make the two evenly mixed, the temperature is raised to 80~90℃ to carry out a prepolymerization reaction, thereby obtaining component A of the grouting material; The concentration of isocyanate groups in the semi-prepolymer is 18-25%.

5. The preparation method of the cement-polyurethane composite grouting material suitable for reinforcement of dense soft rock as described in claim 2, characterized in that, The diluent is one or more of dimethyl methylphosphonate, trichloroethyl phosphate, and divalent ester.

6. The preparation method of the cement-polyurethane composite grouting material suitable for reinforcement of dense soft rock as described in claim 2, characterized in that, The catalyst is one or both of dibutyltin dilaurate and m-phenylenediamine.

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